CAD software wanted

[alah]

Hi everybody; I need some free simple software, only to draw pentagons and save the file with .dwg extesion. Suggestions, please.Thanks, Alberto.

[amspire]

If you can live with DXF format, then there are lots of options. Any program that can read a dwg file can read a dxf file.

For DXF files, you can look at inkscape and librecad.

I was going to suggest qcad, but I see that they have now gone professional, and to get the DWG support, you need to pay 33 euros.

When you specify DWG format, you usually have to say which DWG format since the different versions are not backward compatible. For simple shapes, DWG R12 is basically readable by everything that can read DWG files.

[ebclr]

https://www.freecadweb.org/

[sokoloff]

If you can use DXF, OpenSCAD (free) can do it.

Here's the code sample:

Code: [Select]

// Define the function
module regular_polygon(order = 4, r=1){
     angles=[ for (i = [0:order-1]) i*(360/order) ];
     coords=[ for (th=angles) [r*cos(th), r*sin(th)] ];
     polygon(coords);
}
 
// Draw one near the origin
regular_polygon(5, r = 10);
 
// Draw a larger one centered on [30, 0]
translate([30, 0, 0])
  regular_polygon(5, r = 15);

// Draw a smaller one centered on [30, 30]
translate([30, 30, 0])
  regular_polygon(5, r = 5);
 
That makes this DXF output:
pentagons.txt (rename it to pentagons.DXF)  pentagons.txt (1 kB - downloaded 78 times.)

Which is this preview:
pentagons.png

[SiliconWizard]

I second the use of OpenSCAD. Great stuff. I used it to design custom enclosures.

[alah]

Hi, the best I could do was with inkscape, but it draws the pentagon filled in black. I need to print concentric pentagons outlineson a single page, save as pdf, print to se which size suits my need, then convert to send to a shop to cut some pieces. Help, please and thanks to ALL.

[sokoloff]

Code: [Select]

module regular_polygon_outline(order = 4, r=1, t=0.1)
{
     angles  = [ for (i = [0:order-1]) i*(360/order) ];
     coords  = [ for (th=angles) [r*cos(th), r*sin(th)],
                 for (th=angles) [(r-t)*cos(th), (r-t)*sin(th)] ];
     paths = [[ for (i = [0:order-1]) i], [for (i = [1:order]) order*2 - i]];
     polygon(coords, paths, 10);
}

// Loop from 5 to 21 by 2
for (i = [5 : 2 : 21]) {
    // Draw a polygon of 5 sides, radius of 1, thickness of 0.1
    regular_polygon_outline(5, r = i, t = 0.1);
}
yields this preview:
 pentagons2.txt (5.44 kB - downloaded 66 times.)

And produces the attached dxf: (rename txt to dxf):

[sokoloff]

If you just need this one time and can't figure out the code, tell me what sizes you need and I'll generate a dxf for you matching those specs.

[beanflying]

Hi, the best I could do was with inkscape, but it draws the pentagon filled in black. I need to print concentric pentagons outlineson a single page, save as pdf, print to se which size suits my need, then convert to send to a shop to cut some pieces. Help, please and thanks to ALL.

In Inkscape you can control both the fill and stroke (outline). If you are sending it out to be Laser Cut then SVG format should be fine too as most software will handle that. I am not a fan of doing actual drawings in Inkscape as it is clunky compared to a CAD package.

If you want something to grow into for more complex designs later then Fusion 360 for most smaller users remains free. I actually run my exported nested materials from Fusion 360 through Inkscape to tweak the cut layout (reduce spacing and rotate parts) and line colours before sending the sheets to my Laser for cutting or engraving.